Stage I


Patients diagnosed with Stage I invasive breast cancer have a single location of cancer less than 2 cm (3/4 inch) in size that has not spread to the axillary lymph nodes or sites distant from the breast. Although the majority of women with Stage I breast cancer are cured following treatment with surgery and radiation, some patients may benefit from additional treatment with chemotherapy and/or hormonal therapy. Treatment after surgery is called adjuvant therapy and it may further decrease the risk of cancer recurrence.

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The following is a general overview of treatment for Stage I breast cancer. Treatment may consist of surgery, radiation, chemotherapy, hormonal therapy, targeted therapy, or a combination of these treatment techniques. Multi-modality treatment, which utilizes two or more treatment techniques, is increasingly recognized as an important approach for improving a patient’s chance of cure or prolonging survival. In some cases, participation in a clinical trial utilizing new, innovative therapies may provide the most promising treatment. Circumstances unique to each patient’s situation may influence how these general treatment principles are applied. The potential benefits of multi-modality care, participation in a clinical trial, or standard treatment must be carefully balanced with the potential risks. The information on this website is intended to help educate patients about their treatment options and to facilitate a mutual or shared decision-making process with their treating cancer physician.

Primary Treatment of Stage I Breast Cancer: Surgery and Radiation

The primary treatment of Stage I breast cancer typically consists of surgery with or without radiation therapy. Surgery and radiation are considered local therapies because they can prevent cancer recurrence in the affected breast and surrounding area, but cannot treat cancer that has already spread to other locations in the body. Systemic treatments, such as chemotherapy and hormonal therapy, can treat cancer that has spread throughout the body and may be administered as adjuvant treatment (after primary treatment) for Stage I breast cancer.

Surgery: Surgery for Stage I breast cancers may consist of mastectomy or lumpectomy. A mastectomy involves removal of the entire breast, whereas a lumpectomy involves removal of the cancer and a portion of surrounding tissue.  Because a lumpectomy alone is associated with a higher rate of cancer recurrence than mastectomy, patients who elect to have a lumpectomy are also treated with radiation therapy. The combination of lumpectomy and radiation is called breast-conserving therapy. Clinical studies have shown that breast-conserving therapy is associated with a lower risk of local cancer recurrence compared to lumpectomy alone.[1],[2]

Mastectomy and breast-conserving therapy are the current standard of care for the local treatment of Stage I breast cancers and both are considered acceptable options. Furthermore, breast-conserving therapy and mastectomy have been shown to produce similar long-term survival.[3]

Surgery for early-stage breast cancer may also involve the evaluation of underarm (axillary) lymph nodes in order to determine whether cancer has spread outside the breast and establish the stage of the cancer. This is important to determine whether additional treatments beyond local therapies, such as chemotherapy, are required. For over 30 years, the standard of practice for breast cancer staging has included the removal of approximately 10-25 axillary lymph nodes to help determine whether the cancer has spread. This procedure, called an axillary lymph node dissection, can be associated with chronic side effects including pain, limited shoulder motion, numbness, and swelling.

A newer approach for evaluating whether cancer has spread to the lymph nodes is a sentinel lymph node biopsy. The advantage to this procedure is that it involves the removal of only a small number of nodes (or even a single node), called the sentinel nodes, which are the first nodes to which cancer is likely to spread. Prior to surgery, blue dye is injected near the cancer. The dye drains from the area containing the cancer into the nearby lymph nodes, through the sentinel node(s).  The nodes containing the dye are removed during surgery and evaluated under a microscope to determine whether cancer has spread. Sentinel lymph node biopsy is becoming the standard approach for determining whether cancer has spread to the lymph nodes in women with localized breast cancer.[4]

Research now indicates that sentinel node biopsy appears to be just as effective in determining cancer spread to axillary lymph nodes as an axillary lymph node dissection, and results in fewer side effects in patients with early-stage breast cancer.[5]

Ask the Doctor: How can I Ensure I am Getting the Care I need to Avoid Recurrence?

Ask the Doctor: Understanding the Role of Radiation in Early Stage Breast Cancer

For more detailed information, go to Surgery for Breast Cancer.

Radiation therapy: If a patient elects to have a mastectomy, radiation therapy is not typically administered; however, patients who undergo a lumpectomy typically receive radiation. Radiation therapy is often administered using a machine that delivers a beam of radiation deep into the body where the cancer resides, a technique called external beam radiation therapy (EBRT). These treatments are typically administered five days per week for five to six weeks.

Research indicates that radiation reduces the risk of a cancer recurrence in women ages 50 and older when administered after lumpectomy and hormone therapy. This trial included 636 women who were aged 50 years or older. All were treated with a lumpectomy plus the hormone therapy drug tamoxifen. Approximately half of the patients were also treated with radiation therapy to the breast, while the other half did not receive radiation therapy. Women aged 50 to 59 years appeared to benefit the most from the addition of radiation.

Radiation No radiation
Cancer-free survival 91% 86%
Cancer recurrence within 8 years 3.5% 17.6%

Radiation may also be delivered over a shorter time period using a procedure known as breast brachytherapy. Patients should discuss with their doctor whether this is an appropriate approach for them.

For more detailed information, go to Radiation Therapy for Breast Cancer.

Adjuvant Therapy
The Era of Personalized Medicine
Strategies to Improve Treatment


[1] Fisher B, Anderson S, Bryant J, et al. Twenty-year follow-up of a randomized trial comparing total mastectomy, lumpectomy, and lumpectomy plus irradiation for the treatment of invasive breast cancer. The New England Journal of Medicine. 2002;347:1233-1241.

[2]Lichter AS, Lippman ME, Jr Danforth DN, et al. Mastectomy versus breast-conserving therapy in the treatment of Stage I and II carcinoma of the breast: a randomized trial at the National Cancer Institute. Journal of Clinical Oncology, Classic Papers and Current Comments. 1996;1:2-10.

[3] Veronesi U, Cascinelli N, Mariani L, et al. Twenty-year follow-up of a randomized study comparing breast-conserving surgery with radical mastectomy for early breast cancer. The New England Journal of Medicine. 2002;347;1227-1232.

[4]Edge SB, Niland JC, Bookman MA, et al. Emergence of sentinel node biopsy in breast cancer as standard-of care in academic comprehensive cancer centers. Journal of the National Cancer Institute. 2003;95:1514-1521.

[5] Veronesi U, Paganelli G, Viale G, et al. A randomized comparison of sentinel-node biopsy with routine axillary dissection in breast cancer. The New England Journal of Medicine. 2003;349:546-553.